@@ -78,7 +78,7 @@ func (config *Config) InstallFlags(cmd *flag.FlagSet, usageFn func(string) strin

 	cmd.BoolVar(&config.Bridge.EnableUserlandProxy, []string{"-userland-proxy"}, true, usageFn("Use userland proxy for loopback traffic"))

 	cmd.BoolVar(&config.EnableCors, []string{"#api-enable-cors", "#-api-enable-cors"}, false, usageFn("Enable CORS headers in the remote API, this is deprecated by --api-cors-header"))

 	cmd.StringVar(&config.CorsHeaders, []string{"-api-cors-header"}, "", usageFn("Set CORS headers in the remote API"))

-	cmd.StringVar(&config.CgroupParent, []string{"-cgroup-parent"}, "/docker", usageFn("Set parent cgroup for all containers"))

+	cmd.StringVar(&config.CgroupParent, []string{"-cgroup-parent"}, "", usageFn("Set parent cgroup for all containers"))

 	config.attachExperimentalFlags(cmd, usageFn)

 }

@@ -23,6 +23,7 @@ import (

 	"github.com/docker/docker/pkg/fileutils"

 	"github.com/docker/docker/pkg/idtools"

 	"github.com/docker/docker/pkg/mount"

+	"github.com/docker/docker/pkg/parsers"

 	"github.com/docker/docker/pkg/stringid"

 	"github.com/docker/docker/runconfig"

 	"github.com/docker/go-units"

@@ -241,6 +242,20 @@ func (daemon *Daemon) populateCommand(c *container.Container, env []string) erro

 	}

 	uidMap, gidMap := daemon.GetUIDGIDMaps()

+	defaultCgroupParent := "/docker"

+	if daemon.configStore.CgroupParent != "" {

+		defaultCgroupParent = daemon.configStore.CgroupParent

+	} else {

+		for _, option := range daemon.configStore.ExecOptions {

+			key, val, err := parsers.ParseKeyValueOpt(option)

+			if err != nil || !strings.EqualFold(key, "native.cgroupdriver") {

+				continue

+			}

+			if val == "systemd" {

+				defaultCgroupParent = "system.slice"

+			}

+		}

+	}

 	c.Command = &execdriver.Command{

 		CommonCommand: execdriver.CommonCommand{

 			ID:            c.ID,

@@ -258,7 +273,7 @@ func (daemon *Daemon) populateCommand(c *container.Container, env []string) erro

 		AutoCreatedDevices: autoCreatedDevices,

 		CapAdd:             c.HostConfig.CapAdd.Slice(),

 		CapDrop:            c.HostConfig.CapDrop.Slice(),

-		CgroupParent:       daemon.configStore.CgroupParent,

+		CgroupParent:       defaultCgroupParent,

 		GIDMapping:         gidMap,

 		GroupAdd:           c.HostConfig.GroupAdd,

 		Ipc:                ipc,

@@ -146,14 +146,11 @@ func InitContainer(c *Command) *configs.Config {

 	// This can be overridden later by driver during mount setup based

 	// on volume options

 	SetRootPropagation(container, mount.RPRIVATE)

+	container.Cgroups.Parent = c.CgroupParent

 	// check to see if we are running in ramdisk to disable pivot root

 	container.NoPivotRoot = os.Getenv("DOCKER_RAMDISK") != ""

-	// Default parent cgroup is "docker". Override if required.

-	if c.CgroupParent != "" {

-		container.Cgroups.Parent = c.CgroupParent

-	}

 	return container

 }

@@ -16,7 +16,6 @@ import (

 	"github.com/Sirupsen/logrus"

 	"github.com/docker/docker/daemon/execdriver"

-	"github.com/docker/docker/daemon/execdriver/native/template"

 	"github.com/docker/docker/pkg/parsers"

 	"github.com/docker/docker/pkg/pools"

 	"github.com/docker/docker/pkg/reexec"

@@ -90,7 +89,6 @@ func NewDriver(root string, options []string) (*Driver, error) {

 			case "systemd":

 				if systemd.UseSystemd() {

 					cgm = libcontainer.SystemdCgroups

-					template.SystemdCgroups = true

 				} else {

 					// warn them that they chose the wrong driver

 					logrus.Warn("You cannot use systemd as native.cgroupdriver, using cgroupfs instead")

@@ -9,9 +9,6 @@ import (

 const defaultMountFlags = syscall.MS_NOEXEC | syscall.MS_NOSUID | syscall.MS_NODEV

-// SystemdCgroups indicates whether systemd cgroup implemenation is in use or not

-var SystemdCgroups = false

-

 // New returns the docker default configuration for libcontainer

 func New() *configs.Config {

 	container := &configs.Config{

@@ -40,7 +37,7 @@ func New() *configs.Config {

 			{Type: "NEWUSER"},

 		}),

 		Cgroups: &configs.Cgroup{

-			Parent: "/docker",

+			ScopePrefix: "docker", // systemd only

 			Resources: &configs.Resources{

 				AllowAllDevices:  false,

 				MemorySwappiness: -1,

@@ -99,10 +96,5 @@ func New() *configs.Config {

 		container.AppArmorProfile = "docker-default"

 	}

-	if SystemdCgroups {

-		container.Cgroups.Parent = "system.slice"

-		container.Cgroups.ScopePrefix = "docker"

-	}

-

 	return container

 }

@@ -17,10 +17,10 @@ weight = -1

     Options:

       --api-cors-header=""                   Set CORS headers in the remote API

-      --authz-plugin=[]                     Set authorization plugins to load

+      --authz-plugin=[]                      Set authorization plugins to load

       -b, --bridge=""                        Attach containers to a network bridge

       --bip=""                               Specify network bridge IP

-      --cgroup-parent=/docker                Set parent cgroup for all containers

+      --cgroup-parent=                       Set parent cgroup for all containers

       -D, --debug                            Enable debug mode

       --default-gateway=""                   Container default gateway IPv4 address

       --default-gateway-v6=""                Container default gateway IPv6 address

@@ -647,7 +647,8 @@ set like this:

 # Default cgroup parent

 The `--cgroup-parent` option allows you to set the default cgroup parent

-to use for containers. If this option is not set, it defaults to `/docker`.

+to use for containers. If this option is not set, it defaults to `/docker` for

+fs cgroup driver and `system.slice` for systemd cgroup driver.

 If the cgroup has a leading forward slash (`/`), the cgroup is created

 under the root cgroup, otherwise the cgroup is created under the daemon

@@ -10,7 +10,7 @@ docker-daemon - Enable daemon mode

 [**--authz-plugin**[=*[]*]]

 [**-b**|**--bridge**[=*BRIDGE*]]

 [**--bip**[=*BIP*]]

-[**--cgroup-parent**[=*/docker*]]

+[**--cgroup-parent**[=*[]*]]

 [**--cluster-store**[=*[]*]]

 [**--cluster-advertise**[=*[]*]]

 [**--cluster-store-opt**[=*map[]*]]

@@ -82,7 +82,7 @@ format.

   Use the provided CIDR notation address for the dynamically created bridge (docker0); Mutually exclusive of \-b

 **--cgroup-parent**=""

-  Set parent cgroup for all containers. Default is "/docker".

+  Set parent cgroup for all containers. Default is "/docker" for fs cgroup driver and "system.slice" for systemd cgroup driver.

 **--cluster-store**=""

   URL of the distributed storage backend